Is CoreESIM signal available at the Salar de Uyuni (Salt Flats) in Bolivia?

CoreESIM provides stable 4G/LTE signal in the town of Uyuni and extends to some immediate tourist points, such as the Train Cemetery. However, once vehicles venture onto the vast expanse of the Salar de Uyuni, especially during multi-day expeditions to the distant colored lagoons, cellular coverage becomes exceptionally rare. The geographical isolation and lack of infrastructure across the salt flats preclude consistent mobile data access. Offline resources are essential for these tours.